An automated method for mapping geomorphological expressions of former subglacial meltwater pathways (hummock corridors) from high resolution digital elevation data

Lewington, Emma; Livingstone, Stephen J.; Sole, Andrew; Ng, Felix

doi:10.1016/j.geomorph.2019.04.013

Cited by 20 publications

(23 citation statements)

References 72 publications

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“…Traditionally, eskers have been identified as the predominant meltwater landform within the Keewatin area, although meltwater tracks (MW Tracks ) (e.g. St-Onge, 1984;Aylsworth and Shilts, 1989;Rampton, 2000;Utting et al, 2009;Sharpe 185 et al, 2017;Lewington et al, 2019) and meltwater channels (e.g. Storrar and Livingstone, 2017) have also been recorded.…”

Section: Study Areamentioning

confidence: 99%

“…Landsat ETM+ multispectral imagery were used to inform further high-resolution esker mapping from the 10 m resolution DEM. The automatic mapping approach developed in Lewington et al (2019) was used to create a first pass map of hummock corridors -classified as meltwater tracks here (Appendices Fig. A1) to augment the improved esker map.…”

Section: From 30 M Resolution 215mentioning

confidence: 99%

“…Detailed mapping in northern Canada and Scandinavia has identified the presence of linear tracks variously termed 'hummock corridors', 'glaciofluvial corridors', 'washed zones' and 'esker corridors', typically a few hundred meters to several kilometres wide and a few kilometres to hundreds of kilometres long (e.g. St-Onge, 1984;Dredge et al, 1985;Rampton, 2000;Utting et al, 2009;Burke et al, 2012;Kerr et al, 2014aKerr et al, , 145 2014bSharpe et al, 2017;Peterson et al, 2017;Lewington et al, 2019). These features often contain eskers and hummocks which vary in size, shape and relief as well as 'patches' of glaciofluvial deposits and areas of exposed bedrock.…”

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confidence: 99%

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Large-scale integrated subglacial drainage around the former Keewatin Ice Divide, Canada reveals interaction between distributed and channelised systems

Lewington

Livingstone

Clark

et al. 2020

Preprint

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Abstract. We identify and map traces of subglacial meltwater drainage around the former Keewatin Ice Divide, Canada from ArcticDEM data. Meltwater tracks, tunnel valleys and esker splays exhibit several key similarities, including width, spacing, their association with eskers and transitions to and from different types, which together suggest they form part of an integrated drainage signature. We collectively term these features &apos;meltwater corridors&apos; and propose a new model for their formation, based on observations from contemporary ice masses, of pressure fluctuations surrounding a central conduit. We suggest that eskers record the imprint of a central conduit and meltwater corridors the interaction with the surrounding distributed drainage system. The widespread aerial coverage of meltwater corridors (5–36 % of the bed) provides constraints on the extent of basal uncoupling induced by basal water pressure fluctuations and variations in spatial distribution and evolution of the subglacial drainage system, which will modulate the ice dynamic response.

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Section: Study Areamentioning

confidence: 99%

Section: From 30 M Resolution 215mentioning

confidence: 99%

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confidence: 99%

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Large-scale integrated subglacial drainage around the former Keewatin Ice Divide, Canada reveals interaction between distributed and channelised systems

Lewington

Livingstone

Clark

et al. 2020

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“…Recent automatic detection and mapping methods using high‐resolution ArcticDEM data have also been developed to gain insight into their formation (Lewington et al . 2019, 2020).…”

Section: Database Of Glacial Features and Field Data Setsmentioning

confidence: 99%

A new map of glacigenic features and glacial landsystems in central mainland Nunavut, Canada

McMartin

Godbout

Campbell

et al. 2020

Boreas

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A new digital map of glacial geomorphic features and interpreted glacial landsystems was produced for an area covering ~415 000 km2 in the Keewatin Sector of the Laurentide Ice Sheet (LIS) in Nunavut. The map integrates information from previous surficial geology maps and >14 000 field stations, and is significantly improved by the detailed inventory of ~152 000 glacigenic features using high‐resolution ArcticDEM data and Landsat 8 imagery. From this, we identify and map coherent patterns of landform development (landsystems) between the Manitoba border and the Arctic coast, many of which are entirely new and others that are significantly modified or updated. In particular, we recognize six separate ice streams, including one probable remnant ice stream, and we delineate numerous palimpsest streamlined landscapes with associated ice‐flow trends and relative ages. A continuum of relict terrains with varying basal ice thermal conditions is mapped for the first time in the ice divide migration zone between Baker Lake and Wager Bay. In addition, deglacial cold‐based retreat terrains and preserved warm‐based landscapes unaffected by younger glacial events have been identified. These new georeferenced, multi‐scale data sets and interpreted glacial landsystems provide a comprehensive framework to strengthen reconstructions of the glacial history and dynamics of one of the largest ice domes of the LIS, identify distinct glacial sediment transport paths for applications to mineral exploration, and test numerical modelling of the LIS in support of climate change studies and long‐term evolution of modern ice sheets.

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“…These eskers typically comprise ridges rather than beads and often form in, and are connected to, subglacial meltwater corridors (e.g. Lewington et al, 2019). The southern section of this first network becomes increasingly fragmented, with beaded eskers 125 dominating, and the general pattern is much simpler with few tributaries and a consistent N-S orientation with a remarkable degree of consistent parallel patterning.…”

Section: Meltwater Drainage Imprintmentioning

confidence: 99%

A quasi-annual record of time-transgressive esker formation: implications for ice sheet reconstruction and subglacial hydrology

Livingstone¹,

Lewington²,

Clark³

et al. 2019

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Abstract. We identify and map chains of esker beads (series of aligned mounds) up to 15 m high and on average ~ 65 m wide across central Nunavut, Canada from the high-resolution (2 m) ArcticDEM. Based on the close one-to-one association with regularly spaced, sharp crested ridges interpreted as De Geer moraines, we interpret the esker beads to be quasi-annual ice-marginal deposits formed time-transgressively at the mouth of subglacial conduits during deglaciation. Esker beads therefore preserve a high-resolution record of ice-margin retreat and subglacial hydrology. The well-organised beaded esker network implies that subglacial channelised drainage was relatively fixed in space and through time. Downstream esker bead spacing constrains the typical pace of deglaciation in central Nunavut between 7.2 and 6 ka 14C BP to 165–370 m yr−1, although with short periods of more rapid retreat (> 400 m yr−1). Under our time-transgressive interpretation, the lateral spacing of the observed eskers provides a true measure of subglacial conduit spacing for testing mathematical models of subglacial hydrology. Esker beads also record the volume of sediment deposited in each melt season, thus providing a minimum bound on annual sediment fluxes, which is in the range of 103–104 m3 yr−1 in each 6–10 km wide subglacial conduit catchment. We suggest the prevalence of esker beads across this predominantly marine terminating sector of the former Laurentide Ice Sheet is a result of sediment fluxes that were unable to backfill conduits at a rate faster than ice-margin retreat. Esker ridges, conversely, are hypothesised to form when sediment backfilling of the subglacial conduit outpaced retreat resulting in headward esker growth close to but behind the margin. The implication, in accordance with recent modelling results, is that eskers in general record a composite signature of ice-marginal drainage rather than a temporal snapshot of ice-sheet wide subglacial drainage.

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An automated method for mapping geomorphological expressions of former subglacial meltwater pathways (hummock corridors) from high resolution digital elevation data

Cited by 20 publications

References 72 publications

Large-scale integrated subglacial drainage around the former Keewatin Ice Divide, Canada reveals interaction between distributed and channelised systems

Large-scale integrated subglacial drainage around the former Keewatin Ice Divide, Canada reveals interaction between distributed and channelised systems

A new map of glacigenic features and glacial landsystems in central mainland Nunavut, Canada

A quasi-annual record of time-transgressive esker formation: implications for ice sheet reconstruction and subglacial hydrology

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